The Eggs of Birds 441 
Arctic-breeding owls, where the nesting must take place at 
an unreasonably early and cold date in order to give the 
fledglings time to reach mature strength before the suc- 
ceeding winter assails them, is that these birds deposit 
their eggs at intervals of a week or ten days. In this 
way the mother can envelop in her plumage and keep 
thoroughly warm one egg and a callow fledgling at a 
Fig. 350.—Eggs of Screech Owl. 
time, and is assisted, in respect to the later eggs and 
fledglings, by the warmth of the older voung in the nest. 
“The parrots are a wide-spread and numerous tribe, 
and none of the larger species need lay more than two 
or three eggs, for they protect them in deep holes in the 
earth or in trees, and are able to defend them; but some 
of the smaller parrakeets lay as many as twelve eggs, 
reflecting the greater dangers with which they have to 
